Rear cylinder too rich problem

Hi new friends. Just joined this forum and hoping y’all can help me figure this issue out or at least pointed in the right direction. About six months ago I bought a 2004 v star 1100 classic with 14,000 miles, aftermarket exhaust and already jetted carbs. After a few hours of ride time I noticed some backfiring on deceleration which I now understand is a common V Star issue but back 6 months ago I thought it must need a tune up, carb rebuild and jetting so that’s what I went ahead and started on myself which in hindsight was a mistake. When taking it apart and working on it two things caught my attention: 1. The front carb had excessive gas everywhere and the air filter and housing was drenched in gas. 2. The rear spark plug was totally black and appeared to be running rich. I continued with the rebuild and found the carb had already been jetted when the aftermarket exhaust was installed I’m guessing but being brand new decided to install the new Dino jetting kit I had bought which probably didn’t help me any. Tried adjusting the valves but got too scared and didn’t really actually do any adjusting just lined the things up and checked clearances which were roughly correct I think. Put it all back together and ran a little rougher than I had expected it to run so did some more reading and YouTube watching and learned I needed to sync the carbs now. Also at this point I checked the spark plugs and the rear plug was already completely black after just a few minutes of running. I did the sync the best i could but gauges not in same position so did more reading and found I should probably adjust the mixture screws but only got worse and dark smokey exhaust and lots of knocking and backfiring. Holy shit I thought. What the hell have I done to my new bike here? So took it all back apart and found I had put the carb breathing box rubber connector pieces on wrong side (front on the back, back on the front) and also installed longer PMS screws around this time so I could adjust without taking everything apart every time and put it all together and ran much better but still not quite right and smoke from rear cylinder exhaust pipe. I tried a few adjustments of the mixture screws and even turned the rear screw completely closed but still runs rich with Smokey exhaust so I gave up and that’s how she still sits in my garage right now which is depressing with the amazing Fall weather we’ve had here in Northern California. I decided to just pay a mobile mechanic to fix it for me but everyone is too busy and haven’t got anyone over here yet to do it. I keep reading these forums and it seems like it’s probably a stuck carb float or leak in the vacuum lines or bad petcock and want to get this sucker running good myself so I don’t feel like I was too lame to finish the little project I started. Obviously I’m not a mechanic or know a lot about motorcycles but I do do well with direction from someone who does know about these bikes or is a mechanic so wanted to post this here in hopes of getting some knowledgeable direction from one of y’all who might be able to solve this frustrating riddle. Please & Thank you!